December 1965: December will be remembered for unseasonably cold weather in the last 6 days of the month, especially on the 29th, with unpleasant conditions for holiday makers. Moisture was mainly adequate for pasture growth, and it was a good month for stock. Gales buffeted many districts on the 29th and were exceptionally strong in Wellington.  [Unfortunate timing. Eastern districts in particular had plenty of warm sunny days in the first 3 weeks].
   
Rainfall: Rainfall was somewhat above average over most of the North Island and in western and far southern districts of the South Island. Waikato, some central districts of the North Island, and the greater part of Hawkes Bay received more than 50% above average, as did also eastern Southland and Fiordland. In coastal districts of southern Hawkes Bay rainfall was double the average, with more than half of the month’s rain falling on the 20th, amounting to 2-6”. In Canterbury and North Otago rainfall was mainly less than half the average value. In some inland areas, especially around Lakes Tekapo and Pukaki and the upper Waitaki valley, it was less than a quarter.

Temperatures: Temperatures were mainly close to average. However, Southland and South Otago were 1F-3F cooler than normal, while the Canterbury Plains were 1F-2F warmer. On the 29th there was a general fall of snow over Southland and it lay to a depth of up to 6” in inland districts, especially western Southland. Parts of Otago were also affected, and some heavy snow falls were reported well down on the ranges as far north as Ruapehu.

Sunshine: Sunshine was above average by 20-70 hours in eastern districts from Dunedin to East Cape and also in Bay of Plenty, Waikato and Auckland. The largest departures were in inland Canterbury, where Hanmer received its highest December total for over 30 years. The main area with sunshine below average was the West Coast, mainly by 15-20 hours. Other areas with 15-45 hours less than average were the Bay of Islands, parts of Manawatu, the Waimea plains of Nelson, and the Invercargill-Gore area.

[Some totals: Kaitaia 203, Kerikeri 168 {suspect}, Whangarei 206, Auckland 244, Tauranga 280, Whakatane 270, Taupo 212, Opotiki 239, Hamilton 243, New Plymouth 230, Masterton 274, Gisborne 270, Napier 266, Wairoa 266, Paraparaumu 208, Ohakea 211, Palmerston North 196, Levin 184, Wellington 221, Stratford 220, Ohakune 194, Wanganui 222, Westport 182, Hokitika 169, Greymouth 156, Haast 169, Riwaka 247, Nelson 218, Blenheim 282, Grassmere 239, Kaikoura 245, Mt Cook 171, Mt John 284, Methven 250, Christchurch 220, Tekapo 297, Timaru 203, Waimate 182, Dunedin Aero 183, Dunedin 189, Queenstown 243, Alexandra 242, Invercargill 157, Campbell Is 66, Chatham Is 171].

Sources: NZ Met. Misc. pub. 107 (Climatological table, NZ Gazette) and NZ Met. Misc. pub. 109 (Meteorological Observations) - additional comments by the poster.

Has that sort of thing happened in more recent years? I notice that there is quite a temperature contrast between the two nearby areas of Inland Canterbury and Southland/South Otago re their variation from normal temperatures.

Settling snow at low levels anywhere in NZ during December (let alone late in the month) would probably be extremely rare and I don't think I've heard of any other occasion other than December 1965. Non-settling flurries did occur on the upper Canterbury Plains in early December 1991.